Carrier 48TCA04---A12 CO2 Sensor Configuration, EconoMi$er IV Sensor Usage, Differential Enthalpy

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graph with the left side of the chart to determine that the range configuration for the CO2 sensor should be 1800 ppm. The EconoMi$er IV controller will output the 6.7 volts from the CO2 sensor to the actuator when the CO2 concentration in the space is at 1100 ppm. The DCV setpoint may be left at 2 volts since the CO2 sensor voltage will be ignored by the EconoMi$er IV controller until it rises above the 3.6 volt setting of the minimum position potentiometer.

Once the fully occupied damper position has been determined, set the maximum damper demand control ventilation potentiometer to this position. Do not set to the maximum position as this can result in over-ventilation to the space and potential high humidity levels.

CO2 Sensor Configuration

The CO2 sensor has preset standard voltage settings that can be selected anytime after the sensor is powered up. (See Table 28.)

Use setting 1 or 2 for Carrier equipment. (See Table 28.)

1.Press Clear and Mode buttons. Hold at least 5 seconds until the sensor enters the Edit mode.

2.Press Mode twice. The STDSET Menu will appear.

Table 28 – EconoMi$er IV Sensor Usage

	ECONOMI$ER IV WITH OUTDOOR AIR DRY
APPLICATION	BULB SENSOR
	Accessories Required
Outdoor Air	None. The outdoor air dry bulb sensor is
Dry Bulb	factory installed.
Differential	CRTEMPSN002A00*
Dry Bulb
Single Enthalpy	HH57AC078
Differential	HH57AC078 and CRENTDIF004A00*
Enthalpy
CO2 for DCV
Control using a	33ZCSENCO2
Wall-Mounted
CO2 Sensor
CO2 for DCV	33ZCSENCO2† and	O
Control using a			CRCBDIOX005A00††
Duct-Mounted	33ZCASPCO2**	R
CO2 Sensor

*CRENTDIF004A00 and CRTEMPSN002A00 accessories are used on many different base units. As such, these kits may contain parts that will not be needed for installation.

† 33ZCSENCO2 is an accessory CO2 sensor.

**33ZCASPCO2 is an accessory aspirator box required for duct- mounted applications.

††CRCBDIOX005A00 is an accessory that contains both 33ZCSENCO2 and 33ZCASPCO2 accessories.

3.Use the Up/Down button to select the preset number. (See Table 28.)

4.Press Enter to lock in the selection.

5.Press Mode to exit and resume normal operation.

The custom settings of the CO2 sensor can be changed anytime after the sensor is energized. Follow the steps below to change the non-standard settings:

1.Press Clear and Mode buttons. Hold at least 5 seconds until the sensor enters the Edit mode.

2.Press Mode twice. The STDSET Menu will appear.

3.Use the Up/Down button to toggle to the NONSTD menu and press Enter.

4.Use the Up/Down button to toggle through each of the nine variables, starting with Altitude, until the desired setting is reached.

5.Press Mode to move through the variables.

6.Press Enter to lock in the selection, then press Mode to continue to the next variable.

Dehumidification of Fresh Air with DCV (Demand Controlled Ventilation) Control

If normal rooftop heating and cooling operation is not adequate for the outdoor humidity level, an energy recovery unit and/or a dehumidification option should be considered.

EconoMi$er IV Preparation

This procedure is used to prepare the EconoMi$er IV for troubleshooting. No troubleshooting or testing is done by performing the following procedure.

NOTE: This procedure requires a 9-v battery, 1.2 kilo-ohm resistor, and a 5.6 kilo-ohm resistor which are not supplied with the EconoMi$er IV.

IMPORTANT: Be sure to record the positions of all potentiometers before starting troubleshooting.

1.Disconnect power at TR and TR1. All LEDs should be off. Exhaust fan contacts should be open.

2.Disconnect device at P and P1.

3.Jumper P to P1.

4.Disconnect wires at T and T1. Place 5.6 kilo-ohm resistor across T and T1.

5.Jumper TR to 1.

6.Jumper TR to N.

7.If connected, remove sensor from terminals SO and +. Connect 1.2 kilo-ohm 4074EJM checkout resistor across terminals SO and +.

8.Put 620-ohm resistor across terminals SR and +.

9.Set minimum position, DCV setpoint, and exhaust po- tentiometers fully CCW (counterclockwise).

10.Set DCV maximum position potentiometer fully CW (clockwise).

11.Set enthalpy potentiometer to D.

12.Apply power (24 vac) to terminals TR and TR1.

Differential Enthalpy

To check differential enthalpy:

1.Make sure EconoMi$er IV preparation procedure has been performed.

2.Place 620-ohm resistor across SO and +.

3.Place 1.2 kilo-ohm resistor across SR and +. The Free Cool LED should be lit.

4.Remove 620-ohm resistor across SO and +. The Free Cool LED should turn off.

5.Return EconoMi$er IV settings and wiring to normal after completing troubleshooting.

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